118 



80) inflation of ectotympanic: 0 = not inflated; 1 = slightly / moderately inflated; 2 = 

 inflated (Wozencraft 1989) (Fig.22). 



As with most other carnivores, an inflated auditor}' bulla is common to all phocids, albeit 

 to varying degrees (Howell 1928; Segall 1943; Hunt 1974). It ranges in size from "large" 

 in Leptonychotes to "small" in Monachus tropicalis (King 1972). The inflated bulla of 



Fig.22: Ventral view of the idealized phocid left basicranial region [but based largely on Monachus 

 tropicalis (USNM 102536)] (see inset) illustrating selected characters (indicated by their number: see 

 Character Analysis) of this region. Anterior is towards the top of the page and lateral to the right. 

 Scale bar equals 1 cm. Inset adapted from Lawlor (1979). 



